Defrost Logic - Toshiba ESTIA RUA-CP1701H Service Manual

Monobloc Outdoor Unit

8.4.6. Defrost logic

•
In heating operation, defrost operation is performed when TE sensor temperature satisfies any
condition in A zone to D zone.
•
The defrost operation is immediately finished if TE sensor temperature has become 12°C or more,
or it also is finished when condition of 7°C < TE < 12°C has continued for 1 minute. The defrost
operation is also finished when defrost operation has continued for 10 minutes even if TE sensor
temperature has become 7°C or lower.
•
After defrost operation has finished, the unit switches back in heating mode.
8.4.6.1. Defrost mode on 17kW unit
* The minimum TE value between 10 and 15 minutes after heating operation has started is stored in
memory as TE0.
A zone Status [TE0-TE > 3] continues for 20 seconds.
B zone Defrost operation is performed in this zone when [TE0-TE > 3] continues for 20 seconds.
C zone Defrost operation is performed when this zone continues for 20 seconds.
D zone
Defrost operation is performed when this zone continues for 20 seconds.
8.4.6.2. Defrost mode on 21kW unit
* The minimum TE value between 10 and 15 minutes after heating operation has started is stored in
memory as TE0.
When To is normal
Status [(TEO-TE) – (ToO-To) ≥ 3] continues
A zone
for 20 secs
Status [(TEO-TE) – (ToO-To) ≥ 2] continues
B zone
for 20 secs
Status [TE ≤ 23°C] continues for 20 seconds
C zone
D zone When compressor operation status TE < 2°C is calculated for d minutes
When To is abnormal
Status [TEO- TE ≥ 3] continues for 20 secs
Status [TEO-TE ≥ 2] continues for 20 secs
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Service Manual